The British Tertiary Volcanic Province was created 60-50 million years ago during the formation of the North Atlantic.[1] As the Earth's crust stretched, volcanoes and lava flows erupted along a line from Ireland to the Hebrides. The Giant's Causeway and Staffa are the most famous natural monuments created by this event. Other sites include: Skye, Mull, Ardnamurchan, Arran, Sanday, Eigg, Canna, Rathlin Island and Lundy. The dike complexes of the province contain many examples of dolerite dike swarms.